If you want to understand why Paul Ryan has suddenly become the de facto leader of the sad, pathetic, shriveled thing known as the Republican party, you need look no farther than his response to the classless sandbagging he got from the Bringer of Kinetic Military Action and Vacationer-in-Chief:

“I thought the president’s invitation…was an olive branch. Instead, what we got was a speech that was excessively partisan, dramatically inaccurate, and hopelessly inadequate to address our country’s fiscal challenges… What we heard today was a political broadside from our campaigner in chief. This is very sad and very unfortunate. Rather than building bridges, he’s poisoning wells.”

As I said on the radio yesterday, if anyone had spoken like this to the princeling earlier in his life, he very likely never would have become president. Instead, Obama has been coddled and cosseted throughout his glide-path trajectory — maverick Democrat Mickey Kaus just called him “the biggest affirmative action baby in history,” and said he was a lousy politician to boot. No one, it seems, has ever sat him down and explained to him how thoroughly mediocre he really is. Call it the audacity of mope.

And yet there he is, partying it up in the White House and launching his billion-dollar reelection bid with a speech that would have made Rosa Luxemburg proud, so maybe believing your own myth can take you all the way from Punahou to the presidency without every having to accomplish a damn thing. As the saying goes, “When the legend becomes fact, print the legend.”

Which is why it’s important that the handful of Republicans with spine speak sternly to Obama the way Ryan did. Pace all the number-crunchers and crystal-ball-gazers, he won’t be defeated by conventional means, or by hopeful comparisons to Jimmy Carter, or by competing programs, and certainly not by the weak-tea “collegiality” of Boehner & Co. Playing by the rules doesn’t work when the other team is playing a different game entirely.

There’s no there there with Obama, just the legend of his own invincibility. The sooner the Republicans come to grips with that, the sooner they’ll figure out how to beat him.